2003 Chevrolet Blazer Owner's Manual - Page 150

Defogging and Defrosting (Blend): Use this mode to direct half the air to the windshield and half to the floor outlet. Close the center outlets to help defrost the side windows more quickly. In this mode, the system will automatically force outside air into your vehicle and it will also run the air-conditioning compressor, unless it falls below the temperature at which air conditioning is effective. Rear Window Defogger The rear window defogger uses a warming grid to remove fog from the rear window. Q REAR: Press this button to turn the rear window defogger on or off. An indicator light in the button will come on to let your know that the rear window defogger is activated. 9 (Defrost): This mode directs most of the air to the windshield and the side window vents, with only a little air directed to the floor vents. If your vehicle has heated outside rearview mirrors, when the rear defogger button is pressed the mirrors will warm to help clear any fog or frost from the surface of the mirrors. Notice: Don't use a razor blade or something else sharp on the inside of the rear window. If you do, you could cut or damage the defogger and the repairs would not be covered by your warranty. Do not attach a temporary vehicle license, tape, a decal or anything similar to the defogger grid. 3-2 1